Fifth wheel having a remote controlled locking mechanism



selt 2, 195s O. A. HOLLAND FIFTH WHEELy HAVING A REMOTE CONTROLLED LOCKING MECHANISM 4 sheets-sheet 1 original Filed Aug. 5, 1952 mwN nvm. \\N L INVENTOR.

Sept. 2, 1958 o. A. HLLAND 2,850,292

FIFTH WHEEL HAVING A REMOTE coNTRoLLED LOCKING MECHANISM I N VEN TOR. 'a5/1242@ 67. @Maa/w@ FIFTH WHEEL HAVING A REMOTE coNTRoLLED LOCKING MECHANISM o. A. HOLLANDu sgpt. z., 195s 4 Sheets-Sheet 5 Original Filed Aug. 5, 1952 SPt- 2, 1958 v o. A. HOLLAND 2,850,292

FIFTH WHEEL HAVING A REMOTE CONTROLLED LOCKING MECHANISM Original Filed Aug. 5, 1952 4 Sheets-Sheet 4 \@N www NAN afl/44 w n www, il MSN/ i 59g! Irl E?,

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2,350,292 Fatented Sept. 2, 1953 FIFTH WHEEL HAVING A REMTE CNTRLLED LOCKFNG MECHANISM (lswald A. Holland, Hammonton, N. J.

Continuation of application Serial No. fi, August 5, i952. This appiication anuary 23, i956, Serial No. 5665906 2 Claims. (Cl. 28d-434) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to the art of motor vehicles and particularly to coupling and uncouping equipment for truck-tractors and semi-trailers, and is a continuation of my application Serial Number 302,855, filed August 5, 1952, now abandoned.

it is the primary object of this invention to provide new and improved means for coupling and uncoupling tractors and trailers which means are entirely controlled by the driver of the tractor-trailer combination from within the cab of the tractor.

A further object of the invention is to provide a coupling unit or fifth wheel which can be operated to uncouple the tractor from the trailer while the vehicles are moving and with a full load on the trailer.

This invention also contemplates the modification of conventional trailer landing gear so that the landing wheels will automatically be raised when the tractor is backed into coupling position and will be dropped into supporting position when the tractor is driven away from the trailer even when the uncoupling operation is performed while the vehicles are moving.

Still another object of this invention is to provide means for preventing operation of the coupling unit and retraction or lowering of the landing wheels except when the tractor and trailer are in the proper relationship for so doing and the driver has operated the controls in the cab into the position for performing the contemplated operation.

Another object of this invention lies in the modification of air or vacuum supply hosecoupling units so that the units will automatically uncouple when the tractor is driven away from the trailer and will seal off the air or vacuum hose connected to the tractor when the coupling is separated.

Still another and final purpose of the invention is the application of the aforementioned features to conventional tractors and trailers at low cost and without destroying the capability of the tractor or trailer to be coupled to a conventional trailer or tractor respectively.

it is noted that other automatic coupling units or iifth wheels for tractor-trailer combinations have been attempted heretofore. A brief comparison of these old systems with that of applicant will serve to point out several basic differences which should be kept in mind.

First of all, the known devices require that at least the fifth wheel and landing wheels be replaced while in applicants system only relatively inexpensive modifications to conventional equipment are needed.

Secondly, tractors equipped with automatic couplers other than that of applicant can beutilized only with trailers supplied with similarly modified equipment while a tractor or trailer furnished with applicants modified units can still be efficiently coupled to standard units.

Thirdly, applicant retains the air or vacuum service lf. nu

gi brakes on the trailer While others must resort to less eiiicient mechanical brakes.

Another advantage of applicants system over that of conventional coupling equipment is that the king pin of the trailer upper fifth wheel is completely enclosed by the units of the lower fifth wheel attached to the tractor and these units may be locked in closed position by power operated means which cannot be inadvertently released, whereas, in conventional fth wheel assemblies locking jaws only partially encircle the king pin and are subject to failure due to normal wear.

Last, but very important, vehicles equipped with applicants invention can be uncoupled while the Vehicles are in motion and fully loaded without any damage to tractor, trailer or load, a feat which was considered impossible in the past.

The invention herein described has many advantages and wide utility. Its use will reduce to a minimum the possibility of accidental uncoupling of truck tractors and semi-trailers. When used in shifting operations in yards much time can be saved and accidents averted since the driver need never leave the cab as landing wheels are automatically lowered when `the tractor is driven away from the trailer and accidental uncoupling is prevented.

The invention could also be employed to great advantage in hauling explosive or inflammable materials, by the Armed Forces in combat, or wherever dangerous activities are carried on, for example on aircraft landing fields; in short, wherever the ability to quickly couple to and remove a trailer from its location may become necessary or where it may be important to quickly separate a tractor from its trailer. It will be apparent that in many einer gencies expeditious coupling or uncoupling of a tractor and trailer may prevent loss of valuable equipment or personnel.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Figure l is a side elevation of the new coupling unit and landing gear shown in coupled position on a tractor and trailer;

Figure 2 is a front elevation of the trailer supported by the improved landing gear and showing hose coupling units which are part of the invention;

Fig. 3 is a top plan View of the landing gear showing how contact between the segment on the landing gear and the lower fth wheel serves to operate the landing gear;

Fig. 4 is a plan view looking from the bottom of the lower fifth wheel with the fifth wheel in position for receiving the trailer kingpin and the cover plate removed;

Fig. 5 is a view similar to Fig. 4 but with the kingpin engaged and with the detent forced out of its notch in the locking plate by the kingpin;

Fig. 6 shows a modified form of the invention as seen from the underside of the lower fifth wheel with the locking plate in closed position, the open position being shown in phantom;

Fig. 7 shows the lower fifth wheel as it is about to engage the upper fifth wheel and kingpin and the landing gear segment;

Fig. 8 is a cross section taken on line 8-8 of Fig. 4;

Fig. 9 is a cross sectional view of a fifth wheel having a modified locking plate with the kingpin fully engaged but before the locking plate has rotated into closed position;

Fig. l() shows the modified fifth `fsf/heel in cross section taken on line 10--16 of Fig. 6;

Fig. ll is a section taken on line iiiii of Fig. 3 and illustrates the landing gear in its alternative positions, demonstrating the relative positions or some of the parts;

Yessonne Fig. l2is an enlarged view of the fth wheel shown in Fig. 5 with some of the parts removed for clarity;

Fig. 13 is a detail view of the landing gear locking mechanism taken on section line .1.3--13 of Fig. 3;

Fig. 14 illustrates a'modiiied hose coupling unit for use in applicants invention; and Y Fig. 'l5fis 'an enlarged detail ofV the centerV and locking plates shown in Fig. 6. Looking now at Fig. l, truck-tractor 21 is shown coupled vtosenli-trailer 221 by meansrof the fifth wheel orcoupling-unit 23. Landing gear 24 appears in its normal attitude when the Ytractor and trailer are coupled, that is with the landing wheels in raised position.

Referring to Fig. 3, the lowerV tifth wheel is seen to comprise a generally circular bearing` or face plate 25 provided withrlaterally yextending projections 26, 27 andV rearwardly'extending skid portions 28, 29 which, as shown in Fig.` 7, haveA a Vslight convex curvature. TheY confronting edges 3b, 31'of the 'skid portions form aYV-shaped slot converging toward'the center of the bearing plate 25. This V-shapedslot Vmerges into alsecond slot ahaving Vparallel walls 3,2, 33 and bounded at one end bya semi- Vcircular-walliiwhich. lies substantially concentric with 'a' portion of theside'wall of bearing plate 25. Plate 25 is attached to .thetractor chassis by supports 76 (Figures l Yand 7) held to the tractor by bolts 77 and pivots on shaft'l journaledin bearings 79. VDue ton an unbalancc of weight the bearing plate will assume the attitude shown inFig. V7 when in 'an inoperative position.

Y Theru'pper 'fifth wheel, asjshown in Fig. 7, comprises a circular bearing plate 35 which cooperates with the face plate of the lower fifth wheel 'to support the trailer and a kingpin 336Y having `a diameter equal to the width ofthe second slot 32am the plate 25 and reduced portion 37 intermediate Vits ends. Oblique guideways or skids 38, 39 (Figure 2) extend from the surface of the bearing plate 35,1an'd are spaced apart aY distance substantially equal to the distance between the free ends of skidsl 25, V29 on the lower fthwheel. Y

As shown in the V.Figure k4 modification, a center plate '40 is fixed to the plate Z5 0n the side opposite' its'bearing plate 25;" Aflocking plate 44 (Figures 4 and 8) is rotatably `fitted into the circular Y'recess' of the center plate 40.

and is retained therein by `a cover plate 45. A slot 46 (Figures 5 SandV 12), substantially coinciding with the slots in thebearing plate 25 and the center plate 40 is providedjin the cover plate 45 .and a slot 47 of a width corresponding substantially to the diameter of the reduced portion 37 in the kingpin 36 is formed 'in the locking plate 44. ,This slot V47 merges into an arcuatewall 48 which has [a -diarnetenV slightlylarg'er than the width ofV slot 47.

lnfa modified form of the invention .shown in Fig. 9,

the recess 49 extends through the whole thickness ofthe center plate 40 and the locking plate44 is Vproyidedwith arm ory shaft (Figure 5) of an electric solenoid or an air or vacuum motor 54. Pin 53 is `located on a line approximately 85 from the axis ofjslot 47 when the slot is in the positionV shown in Figures 5 and 12. Slidably mounted in a bore 59 (Figures 8 and 12) in center plate 40 and with its end 60 alternatively eng-aging one of the notches 56, 57 is a detent 58. The other end V61' of the detent is supported in a bearingr62 xed to the bottom of bearing plate 25. A spring 63 urges the detent into engagement with the notches 56 and 57. An indicator rod 64 having markings 65 is also rotatably attached at one end to pin V53 and is slidably supported intermediate its ends by a` support member 66 xed to the underside of plate 25. Y A block- 67V is also attached to d the plate 25 and swivelly supports the solenoid or fluid motor 54 by means of pins or bolts 68. In the case where 54 is a solenoid, current is supplied to the coil from the tractor electrical system through a switch `in the Cabot the tractor which Vcan be operated by the driver of the vehicle to provide a tiow of currentto operate the actuating arm or armature 55 in the direction desired. Where 5,4 is a vacuum or air 'motorpa cylinder 69 is Vprovided with ttings 70 and 7l at eachr Vend thereof and a piston 72'connected to the shaft 55.' A valve in thecab may be operated to supplyatmos-L -pheric pressure to one end of the cylinder through one of the fittings and either air' under pressure from the trucks air supply orkvacuum from the intake manifold to the other end of the cylinder to eiect operation of the shaft 55, and consequently rotate the locking plate 44 to which the shaft is swivelly connected by means of eyelet or bearing 73 Vand'operatingpin 53. When the locking plate is in open position the markings on indicator rod 64 are not visible and when the locking plate is closed the markings cany be seen beyond the edge of plate 25 as shown in Figure 5. Aylatch dog 74 is rigidly secured to the detent 58 vand Vis A.offset `laterally Vto provide clearance forthe pin 53 andvertically to clear Ythe cover plate 45.. The freeY end Vof this'dog isV formed with a cam face 75 which .underlies the arcuate wall 48 when thedetent is Yengaged with oneV of the notches 56, 57 and isV provided With a .thin boss 75*to bring the Vend of the cam vface into the 52 in the cover plate 45.

Supposing that it was desired Yto couple the ,tractor to the trailer'when the trailer was in -a parked position v Ysupported on its landing wheels'and. the locking plate Y' 58 being engaged with notch 57 and the locking plateV twoslots each extending partly throughthe thickness of theplate, one slot 5t? being identical to the slot `47, 4870i the form described'above ,andV theV otherrslotl substantiallycoinciding with theslotsrlay and 46 inthebearingV Projecting fromra suriaceof'the locking plate 4r4l (Figi' uresrS andfl2) and extending through Va clearance groove 52 in the coverrrplate 45 is a locking plate operating pin 53 and pivotally connected to this pin is the actuating was in the position showniniFig. 4. The Vdriver would operate the switch or valve in the cab to the positionv Vwhichgwould cause rotation of the locking plate to rthe 'attitude in which it is shown'in Fig. 5. However, movement of the locking plate would be prevented by detent would remain in its open position. The tractor is backed towards the trailer with the king-pin in linejwiththe VV-'Shaped slot 32a in Vthe plate 25. :The skids 38, 39 will engage the inclined surfaces 28, 29 and gradually transfer Y the weight of the trailer from the landing .wheels to the i bearing plate which will tilt into a horizontal position as the .point at Vwhich Vthe trailer weight YisfsupprortedV on the plate' 25 passes overthe shaft 78. Thekingpin will be guided 'into4 the slots in the'bearing plate ,25, center plate 40,7locking'plate 44 andVV cover plate 45 and as it Y nears the end ofthe slotsthe' portion Y80 of the. kinge pin 36 will engagethe cam face 75 of the latch dog 74n forcing it Vand the latch back against the pressure of spring 63, thus releasing thelocking plate for actuation by Vmotor 5,4 Yto theposition shown in Fig'. 5. The Ylandingrwheels will be `raisedV as hereinafter appearsgand VtheV markingsY 65 vwill be exposed. The Vtractor isthen Ydrivenforward and since the diameter of the portion ofV the slot bounded by wall 4S is slightly larger than the Ireduced portion of'pin 36, the kingpin moves rearward which permits theV latch dog 74to move rearward and the detent 58 to, engage Vthe notch 56. y The locking `plate clearance ,groove will thus be retained against rotation, and accidental uncoupling of the trailer while the tractor is moving forward, will be electively prevented. As seen in the drawings the kingpin is entirely surrounded so that its accidental escape from the lower fifth wheel is unlikely and the pulling force of the tractor is exerted against all of the surface ofthe kingpin 36 contacted by the bearing plate 25, center plate 40 and locking plate 44. Furthermore, the locking plate is rotated approximately 95 which further helps prevent accidental uncoupling since in normal pulling attitude of the tractor there will be practically no component of force tending to rotate the locking plate. Motor 54 is actuated in a'direction to keep the locking plate in its closed position, but should power to the motor fail, detent 58 acts as a safety catch to prevent rotation of the locking plate. Air or vacuum hoses are coupled manually.

When it is desired to uncouple the tractor from the trailer with the vehicles standing, the operator manipulates the controls to the position which will provide power to the motor 54- to open the locking plate. The detent 58 will be engaged with notch 56 and will prevent rotation of plate 44 until the tractor is backed slightly toward the trailer. There is a slight clearance between operating pin 53 and the adjacent edge of the latch dog 74 when the detent 58 is engaged with 56 so that when the tractor is backed the kingpin will strike the cam face 7S causing the latch dog to move back against the pressure of spring 63 and carry the latch with it so that the locking plate 44 is free to rotate. The motor S4 will, thereupon, pivot the plate 44 to its open position. Opening motion of plate 44 stops when pin 53 strikes the abutment 81 at the end of the clearance groove 52 in the cover plate 45. .The tractor is then driven forward which permits the landing wheels to be automatically lowered and locked in position and the detent 58 to seat in the notch 57. Air or vacuum hoses are automatically uncoupled.

To unhitch the trailer while the vehicles are moving, the driver need only decelerate momentarily'after having operated his controls to the position for opening the locking plate. This will cause the trailer to ride up on the tractor and the kingpin to force the latch out of the notch 56 thus permitting the locking plate to be driven to its open position. Upon re-acceleration of the tractor, the kingpin will slip out of the lower fifth wheel and the tractor will move away from the trailer, the landing gear automatically lowering as this occurs. The air or Vacuum hose couplings will also be separated, the porA tion of the coupling attached to the tractor will bo sealed o" to prevent loss of air or vacuum supply and the trailers brakes will be applied to bring the vehicle to a stop, all as hereinafter explained.

In the form of the invention shown in Figures 6, l5 and 10, no motor or solenoid is required to rotate the locking plate. instead the kingpin causes rotation of the locking plate as it is moved linearly with respect to the lower fifth wheel and the motor or solenoid is utilized only to release or engage the detent.

in this modication center plate 82 is provided with an eccentrically disposed circular aperture 32 extending through the thickness of said plate and locking plat-e S3 is rotatably disposed in said aperture. Locking plate 33 is formed with a radial slot 84 which extends through about half the thickness of said plate and is closed at one end by a semicircular wall 85. The Width of slot 84 is slightly greater than the diameter of the kingpin 36 of the upper fth wheel so that the kingpin may slide freely in the slot during Coupling and uncoupling oper ations. A second slot Se of a width slightly greater than the reduced diameter of the kingpin is formed in the remaining thickness of the locking plate 83 overlying slot 84 and terminates in a semicircular wall S7, walls S5 and 87 being concentric with each other and with wall in bearing plate .25 when the locking yplate is in its closed position. A stepped opening Sii through the wali of the center plate has a cross-section substantially duplicating the cross-section of slots 84 and S6 in the locking plate 83 and lies in line with the slot 32a in the bearing plate. The locking plate 83 is held in place by a cover plate 39 bolted to the center plate and having therein a slot 9h closed at one end by a semicircular wall 91. Slot coincides with slot 32a in the bearing plate 25. A stop pin 92 projects from the locking plate S3 and cooperates with a curved slot 93 in the cover plate 89 and abutment 94 to locate the locking plate in its open position so that opening 88 mates with slots 84 and 86 to permit entry or exit of the kingpin. An air or vacuum motor or solenoid 95 is attached to the underside of face plate 25' by means of a yoke 96 and bolts 97 and may be energized to operate a latch or detent 9S which projects through a groove 99 in the centerplate 82 and when the locking plate is in closed position engages notch provided on the periphery of the locking plate. Notch itli is somewhat wider than the latch to insure engagement of the latch with the notch when the locking plate is revolved to closed position. A shaft 101 actuated by the solenoid or motor 9S extends therethrough and has its one end connected to the detent 98 while its other end carries a removable handle 163 by means of which the detent may be manually operated. A spring m2 is compressed between the detent 98 and the motor housing and urges the detent toward latching position, as a precautionary measure in case of failure of motor 9S. During normal operation of the vehicles the motor is energized to thrust the detent into latching position but for uncoupling the tractor from the trailer the operator of the vehicles may actuate the motor by means of controls in the cab of the tractor to withdraw the detent from notch The angle between the end of latch 9h and its edge tace 5.04 is made somewhat less than 90 and the edge of notch ith? is inclined in the same direction. This structure causes to be imposed on the face 104- a component of force tending to urge the detent into the notch l, thus reducing the possibility of disengagement of the latch when the tractor is pulling the trailer. vThe force from plate 3 is transmitted to detent 98 near the end 104 in a direction radial to detent 98 (see Figure l5). This radial force in turn is transmitted in a direction normal Ato face i914. This force normal to the face has a component to the left, or in a direction to keep the detent 98 in the notch.

To uncouple the tractor and trailer when the tractor is pulling the trailer, the driver operates the control in the cab to the position which powers the motor 95' to retract the latch 98 anddecelerates momentarily. This deceleration removes pressure from the edge face 104 and permits the latch to be withdrawn from notch lili). Upon re-acceleration of the tractor the kingpin will pull against the wall of slot 86 and owing to the eccentricity of the point of application of this force with respect to the outer periphery of the locking plate 83 and the aperture in center plate S2 a moment of force is created tending to rotate the locking plate to its open position. The plate 83 will continue to turn under the inuence of the kingpin until the stop 92 engages abutment 94 in the cover plate S9. In this position of the parts the edges of slots 84 and S6 will substantially coincide with the edges of the opening 88 in the wall of the center plate and the walls of slots 84 and 36 will be disposed at an angle with respect to the walls of the stepped opening 3 and the slot 32a in plate 25. The kingpin 36 will slide out from the lower iifth wheel and upon that happening the landing gear will automatically be lowered, the air or vacuum hose couplings between the tractor an-d trailer disengaged and the trailer brakes applied.

To couple the vehicles together, with the locking plate open, the driver of the tractor sets the control in the cab for operating the motor 9S in the direction to engage the latch in notch 109. He then backs the tractor to-v provides Va 'connection between the n i 233. and the landing wheel supports. A rod'241'is`atward .the trailer so that the kingpin enters the slots 32a and 8,8 Yand strikes the wall of slot 84 causing the lock- Y ing plate 83 to rotate and permitting detent )8V tobe driven into the notch` 100 in said locking plate. At the Y same time, the landing wheels will automatically .be

209 pivotally mounted .intermediate their ends by meansV of elongated holes 249 in sidesito and 208 on a bracket 203 which is. secured tothe frame 294 of the trailer and also serves as a housing for .part of the mechanism associated. with the. landing gear. supports 202 include an axle .205 secured .in place by Vlocking collars 210. A crossbar or brace 211 is provided between the supports 202 and to prevent bowing of the axle .201 when a heavilyV loaded trailer is carried by the landing wheels one end of a brace 212 is attached to said axle by a collar 213 and the other end thereof is fixed .tothe crossbar 211. The' inner side 206 of each of supports 202 is made heavier than the other three sides and atits top or free end is provided with .teeth 214 and 215 .and the top edge of the front side 227 of the box girder is .provided with a tooth 216. A stub shaft 217 .has one of its ends journaled in the housing 203 and is journaled intermediate its ends in the trailer frame 204. Locking collars. 21S and 219 serve to maintain the stub shaft in` position. A safety catch 220, provided withteeth 221 and 222 at its free end is pivotally mounted near one end of the stub shaft Vwithin Vsaidhousing and has secured to its top edge a bar or lifting lug 223 which extends over apawl 224 which is keyed as at 224 to said .stub .shaftadjacent the catch 2201and carries .a

The pivot means for the tooth 225 .at'its free end. A camfollower or lever 226 Y is Ykeyed near the other end of shaft 217.

When the landing wheels aredown in ay position to support the trailer, each tooth 225 of the pawls 224 engages tooth 214 onV each of the supports 202, each tooth 221 on the safety .catch engagesits corresponding tooth 216 and a rigid dog 227 on each of the housings 203 cooperates with its respective tooth 215 to maintain the landingV gear inproper vertical alignment. Y n l In Fig. V1l are ,seen an arcuatersegment 22S and two push rods Yor' rams 229, each having one end attached Y to the segment andwbeing slidable inV sets of guide'bearings, 23,0, :2.31 and 232 xed Vto the trailer frame. Rigidly secured between the push rods is aV-horizontal` cross Ybeam 233and depending therefrom4 are vertical channel members or arms 234-located inwardly ofthe push rods. Tension springs 235 are `strung fromeyebolts 236 onthe trailerV frame toreyebolts 237V on the crossV beam and operate tourge the push rods to their extremeforward positiorn AA rod or `shaft 238.. is carried' between. the lower ends of the arms 234 y.and has pivotally Vmounted thereon Ynear each of its ends a connecting link Y239 which Y arms andcross beam ta'chedrto the edge of side 205er thesupport frame by means'of yokes 242'and collars 243 and passes through an elongated aperture 244 in each ofthe links 239. Thus a connection is produced which provides for some lost -8 Y the elongatedrholes vv249 sufficient to disengage dogs 227-V f-romiteeth 21'5, lpawl 224 andcatch 220 remaining er1-- gaged. f Further relativevrnovernent ofthe tractor toward' n the trailer {causes rollers 24S on 'th ends of skid portions' 2.3, 29 to engage .theinner periphery of thejsegment228 andrforce it'back, causing the push rodstoslide inftheirj bearings againstthe resistance of springs v235 r'carrying cross beam 233, verticalarms 234 and links 2,39'wit'n:` ther'rnr A -cam Y240' securedv to eachY of `thel,-pnsh;rods' stri-kes the'.cznnffollower 226 when backward motion of the rams 229 begins and causes Vthe cam Vfollower to ro-j,

tarte stub shaft217 `to which it is keyed against-the pres@Y sure of a'spiing 25.0, disengaging pawl 224 from tooth 214; As pawl 224 is raised it contacts the lifting lug223 and'lifts Vsafety Ycatch 220 Vout of engagement with tooth etweenthe tractorjand trailer when the tractor is .moved into coupling position, thus reducing Vthe possibility of damage .to parts. Cam 240 will lmove outfrom iunder follower 226 allowing stub shaft 217 'to rotateso that pawl 224 and catch 220 will be in position toengage the (teeth 215 on box frame whenY it is Vswung to trailer supporting position. The upperedge lof abutment 253 of the housing limits downward movementeofrthe pawl 224 'andr'catch 225.V By providing individual .stub fr shafts 217 rather than a continuous shaft, fbet erfengagement of the teethand latch means is obtained, since Y failure of the latch means on one side to rotate to fully engaging position will not alect engagementofthe latch means on the other side.

The landing wheels willV be held in the raisedk position Y bythe rollers on the ends of theV lower fifthwheel engaging the segment 228 wherever the vehicles are coupled together. To provide a more even-pressure onsaid seg'- rnent and greater stability of ther-vehicles when the tractor and trailer are being jack-knifed or driven in `a sharp turn,

to each other as. shown in Figure 6.

When-the vehicles are being uncoupled vand .the lower f and the wheels will be driven Vto their supportinggposition by the weight of the .landing gear and by the thrust of springs 235 .acting through arms'234 vand links 239 until the sides'V 207 of the box Vframes impinge Aupon the stop members 252 and 253 fastened across the lfront* and rear respectively of eachV housing203. Camf240 motion between the cross beam V233anfdV rod 241 to pe'r- Vmit easier engagement ofthe lockingV means associated writhjthe feethziazis and 21s. spacers 24s, 246 and 247 may be provided to maintain alignment of links 239. When the tractor 21 is backed 'towardrtrailer 22 for coupling, the upper fth wheel rides up on skid portions 28, 29V and vthe trailer is lifted ontoY the lower VtifthY wheel carried by the tractor. This causes relativervertical mol.V l

tion between housing 203 and supports 202 because Yof Vwill move to a position jwith respect to the follower' 226'which will permit rotation of the stub-shaft suieient to engage catch 220 and pawl 224 with teeth 216 and 214 respectively and as the lower fifth wheel moves completely out of trailer supporting position, theV weight of the trailer will be transferred to the landing gear as axle 205 `moves downwardly inthe elongatedholes 249 Vpermitting dogs 227 to engage-teeth 21.5.Y Y

' f If by reason of unevennessV in the road surface or some other cause proper engagement' of-Vteeth 2,14, 215 land,VV

216 isnot etected due tothe supports 202 not reaching the full vertical position, tooth 222 of the safety catch,"

will'engage'tooth 216 so'that the supported by the landing gear.- Y When the upper` fth'rwheel trailerV may still be inV any vacuum or pressure hose lines between the traclateral `extensions 26, 27 have beenrprovided Y Y on the lower vfifth wheel to'engage thejsegment V22Sjwhen the vehicles are at a relatively steep angle with respect K has become complet-ely; disengaged from the lower fifthrwheel Vand the `tractor continues to be driven from the trailer until the slack" tor and trailer is taken up, additional relative movement of the tractor from the trailer will cause the hose couplings 254 to be separated as hereinafter described.

Hose couplings 254 each include a first coupling unit 255 and a second coupling unit 256, said rst coupling unit being attached to the hose connected to the tractor and said second coupling unit being attached to the air or vacuum line on the trailer.

The first coupling unit comprises a hollow throat portion 257 internally threaded as at 258 near its free end to receive a hose tting and merging into a circular chamber 259, said chamber also being internally threaded to receive a shouldered plug 260. End plate 261 of chamber 259 has a central bore 262 and is provided with an annular recess 263 opening into said bore. A flanged resilient washer 264 of rubber or the like material is -located in said bore with face 265 of said washer pro jecting beyond outer face 276 of said end plate and the flange 266 `of the washer being confined in the recess 263. Plug 260 is counterbored as at 267 and has a reduced central bore 268. A valve disc 269 having cylindrical axial projections 270 and 271 extending from its opposite faces serves to close the bore 262 to prevent the ow of fluid through the throatportion of said first coupling unit. Projection 270 is slidably tted into reduced bore 268 and is counterbored to receive a compression spring 272 which normally urges the valve disc into closing position. The opposite projection 271 passes through the 'bore 262 and in the'closed position of the valve protrudes substantially beyond the free face of washer 264. A sector 273 is arranged radially on the periphery of chamber 259 opposite the throat portion 257 and extends for approximately on either side of the longitudinal center line passing through said throat portion. An arcuate locking lug 274 is formed integrally with coupling unit 255 and located diametrically opposite sector 273 spaced from the face 276 and a stop pin not shown, extends between one end of locking lug 274 and outer face 276 of the end plate 261.

Unit 256 likewise has a hollow throat portion 277, cylindrical chamber 278 having its one end closed by end plate 279 which is provided with a bore 280 and with an annular recess 281 opening into said bore. The annular recess receives flange 282 of a anged resilient washer 283. A cup shaped strainer 284, having a closed end 287, projects through the Washer and is retained by a shoulder 285 which engages the Washer. The strainer is provided with cutout portions 286 in its wall adjacent its open end and with passages 288 consisting of a series of drilled holes adjacent the edges of the closed end 287. The other end 289 of chamber 278 is formed integrally therewith and is provided with a drilled hole 298 located centrally of the end 289. A bolt 291 projects through hole 290 with its head 292 providing an abutment which engages the center of the closed end of the strainer. An adjustable shoulder 293 `on bolt 291 engages one side of the end 289 of the chamber and cooperates with a nut 294 on the other side of end 289 to hold the bolt in adjusted position. A seal is eiected by means of washer 295 backed by washer 296 and located under the nut 294. It may be seen that when the two coupling units are placed together in face to face relation, the closed end of the strainer will abut projection 271 of the valve disc and force it 'back thus allowing the ow of iiuid from throat portion 257 through the valve and into throat portion 277. A passage for uids is thereby provided between the tractor and the trailer.

The remaining structure of coupling unit 256 is simil lar to that of unit 255, there being a sector 297, a locking lug 298 and a stop pin, 275. To couple the units 255 and 256, they are placed in face to face relation with their longitudinal center lines approximately 90 removed and with the stop pins adjacent each other. The units are then pressed together to engage sector 273 Lunderneath lug m9 and sector 297 underneath lug 274 and rotated until an edge of sector 297 engages the stop pin on unit 255 and an edge of sector 273 engages stop pin 275. At this point, a spring pressed ball detent 300 in locking lug 274 drops into a notch 301 provided in sector 297 and a similar ball detent 302 in lug 298 mates with a notch 303 in sector 273 to help maintain the units in assembled position.

Whenever the tractor is uncoupled from the trailer and moved away, slack is taken up on hoses 299 and 304 which extend from the air, vacuum or other fluid supply on the tractor to the trailer. springs 3-05 causing a pulling force to be imposed on coupling 254. This force rotates unit 255 with respect to unit 256 and when the units are rotated approximately 60 relative to eachother so that sectors 273 and 297 are disengaged from locking lugs 298 and 274 respectively, the units will come apart and spring 272 will seat the valve disc 269 sealing oi the supply hose. Coupling units 256, attached to the trailer are disposed at an angle to facilitate coupling and uncoupling of the fluid lines. Conventional equipment on trailers will respond to a break in the fluid line which causes the line to impose atmospheric pressure on the equipment by applying the trailer brakes. Therefore, when the tractor and trailer are uncoupled and the units 255 and 256 separated from each other, unit 256 will open to the atmosphere and the trailer brakes will be applied, bringing the trailer to a stop supported by its landing wheels which will also have been lowered by the uncoupling process as hereinbefore described.

It may be seen, therefore, that applicant has provided safe, efficient means controlled by the driver of the vehicles for coupling and uncoupling a truck-tractor and semi-trailer wherein only the fluid supply hose need be coupled manually and wherein the entire uncouplng process requires no manual operations outside the cab and may be performed while the vehicles are. moving.

Applicant prefers to fabric-ate the ifth wheel and landing gear units from steel plate though they may be cast as in the conventional practice. The parts may be stamped out and welded or otherwise joined. The fabricated construction eliminates cracking and'distortion encountered with cast steel parts and enhances durability and strength of the fth wheel and landing gear.

Obviously many modications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. In a fifth wheel assembly for a tr-uck and trailer; a bearing plate mounted on the trailer; a kingpin which is secured to the trailer bearing plate and extends downwardly therefrom, said kingpin having a reduced diameter portion intermediate its ends; a base plate mounted on the truck, said base plate having an exposed upper bearing surface for selective engagement with the trailer mounted bearing plate, said base plate Aalso having an elongated slot which extends inwardly from a peripheral edge of the base plate and terminates on an internal substantially semi-circular wall; yan annular center plate secured to the base plate on a side opposite its bearing surface, said center plate having a slot in alignment with the slot in the base plate; a circular locking plate rotatably positioned within the annular center plate, said locking plate having a slot and a centrally disposed bore, said slot extending betwene the bore in the locking plate and its peripheral edge, the width of the locking plate slot being but slightly greater than the reduced diameter portion of the kingpin, and the diameter of the said bore being greater than the reduced diameter portion of the kingpin a predetermined amount but less than the diameter of the end portions of the kingpin, said locking plate also having a pair of notches in its peripheral edge, onel notch being substantially opposite the slot in the locking.

This tensions support Vbase plate opposite `theY base plate slotk `and- .engageable with either 4,of the l.not/ches, in thel lockingplate; a ,latch dog rigidly secured to the `detent and disposed such Y that said do'gextends beyond the base plate semi-circularY wall when the detent engages either lof said notches; an air moto;- connected at one end to thelocking plate andk at its other end to the base plate; and control means for the airrmotor whereby ffullcont'rol of the rotary disposition of the locking plate withinthe base plate between its two detent notch engaging positions is maintained.

2. ,'In a fifth `wheel assembly for a trailer and a truck having a cab; a bearing Vvplate mounted on the trailer; a Kingpin which is secured to the trailerbearing plate and extends downwardly therefrom, said kingpin having a reduced Jdiameterportion .intermediate its ends; a base plate mounted on the truck, said baselplate having an exposedfupper bearing surface for selective engagement with the trailer Vmounted bearing plate, said jbase plate also having -an elongated slot which extends inwardly from a peripheral edge 4Vof the base plate and terminates on an Vinternal substantiallyy semi-circular wall; an annular center plate secured lto the base plate Von a side oppositeits bearing surface, saidrcenter platehaving a slotin alignment with the slot in the base plate; a circular locking plate rotatably positionedwithin the annular center/plate, said locking plate having a slotl and a centrallydisposed bore, said slot extending between the bore in the lockinggplate and itsvperipheral edge,.the width Lof the locking plateslot being but slightly greater Vthan Y 12 the vreduced diameter portion of the kingpin, and the diameter .of the said bore being` greater than the reduced diameter portion.k of the kingp'in' a predetermined amountV but less than the diameterzofthe end portionsof the kingpinysaid locking `plateealso having a pair of notchesjin its peripheral edge, one notch vbeing substantially kopposite the slot in `the Vlocking plate and the other notch` being substantially attright angles therewith; a detent slideably positioned on the baseplate opposite .the base plate slot and engageable with'either .of `the notches im the` locking plate; a latch dog rigidly secured to the deA tent and disposed such Athat said doglexten'ds beyondthe base plate Ysemi-circular wall when `the .detent engages4 eitherof said 'notches;.an air motor connected-at one .end

tothe lockingplate and at its other endto the base ,pl-ate; and means in the cab for controlling energization tot. the air motor-therebyrideterniining the rotary dispositionV of the locking ,plate within thelbase plate between its two detent notch engaging positions.v

References Cited in thele of thispatent UNlTED STATES PATENTS Germany Aug. 

